Imported grass Static Mesh aren't interactive in ThirdPersonExampleMap Level

imported grass Static Mesh aren’t interactive in ThirdPersonExampleMap Level


I upload a content from the Epic Games library named : “Temperate Vegetation: conifer Bushes & Saplings I”, this content offer Static Mesh of bush, tree and grass, there is a Level called “Showroom”, this Level has foliage of those tree, and when a ThirdPersonCharacter go through they bend, they also bend over an actor called CollisionBall :

In the “Showroom” Level all the mesh bend like this :

But the “ThirdPersonExampleMap” Level (the ThirdPersonExampleMap) they don’t bend :

I didn’t change any setting, I just use the Foliage paint brush and add the Static Mesh of the tree into the brush: